#include<iostream>
using namespace std;
int n;
int main()
{
	while (cin >> n , n) {
		string ans;
		cin >> ans;
		int y[100] = { 0 };
		int r[100] = { 0 };
		for (int i = 0; i < ans.size() - 1; i++) {
			if (ans[i] == 'Y') {
				y[0]++;
			}
			else {
				r[0]++;
			}	
		}
		if (ans[ans.size() - 1] == 'B') {
			if (r[0] == 7) {
				cout << "Red" << endl;
			}
			else {
				cout << "Yellow" << endl;
			}
		}
		else {
			if (y[0] != 7) {
				cout << "Red" << endl;
			}
			else {
				cout << "Yellow" << endl;
			}
		}
	}
	return 0;
}